The effects of several additions and heating velocities on the firing characteristics of the injection molding of ceramics were studied.
Stearic acid and D. E. P. added to polystyrene as the lubricant or the plastitizer gave favorable results for improving the plasticity of the mix. Particularly, D. E. P. showed the best heating properties which mainly come from its low volatilization temperature.
Taking into consideration the effect of stearic acid on the heating properties of molded ceramics it was confirmed that the amount should be kept less than 4%.
As the heating velocity has remarkable influence on the heating properties the heating schedule should be determined by taking into concideration of the kind of agents, and the thickness of the article.
The molded articles of 6mm thick (Al2O3-styrene-stearic acid-D. E. P. system) must be heated with the velocities less than about 7°C per hour.